In the early 1980s Northern Telecom introduced the Norstar, a scaled-down version of their SL-1 all-digital switch. The Norstar was the first all-digital system suitable for small-sized offices (up to 192 lines), and became one of their major product lines.

The Norstar was powered by a 16 MHz Motorola 68000, and used only a fraction of the CPU's power. Nortel executives were interested in finding ways to use that excess power, as long as their customers paid for the privilege. Nortel asked their research arm, Bell Northern Research (BNR), to look for ways to spend those cycles.

Some time in the mid-1980s a complex project evolved that would deliver a large terminal onto every user's desk, combining a color screen, keyboard and telephone. The Meridian would be used to run various application software in a timesharing fashion. Since the Apple Macintosh had been recently introduced, the system was also to support a rudimentary GUI based on character graphics.

While impressive in concept, the Norstar was simply not up to the task of driving such a system. A similar amount of processing power was needed to drive the single-user Macintosh, so how it is that the BNR developers felt that they could drive multiple terminals as well as telephony from the system is something of a mystery. The system was extremely slow, taking over a minute to open a window for their rather basic spreadsheet for instance. Project managers continued to report the system was on-track and just needed a little more time to complete, even though this was clearly not the case.

After millions had been spent on the project, Nortel management finally gave up and decided to cancel it. In the midst of this a group of three engineers suggested that they could use portions of the system to deliver a voicemail system very quickly, and at least salvage some of the money spent so far. Management accepted the proposal, and the three (two brothers and a longtime friend), styling themselves as the Toronto Ideas Group, soon had a demonstration system up and running.

As development continued stability appeared to decrease. The developers became increasingly convinced that there was no problem in the system itself, and started to suspect that one of the former project's managers was attempting to make them look bad. In order to test this theory they wired the shutter release of a camera to the reset switch on the machine, placed the camera under a hat, and set up a clock within the camera's view of the machine. They did not have to wait long before they captured a rather clear picture of one of the middle-managers resetting the machine at 2AM. The manager in question was not reprimanded, but instead promoted to another group.[citation needed]

With this problem out of the way the system continued to improve. It was soon on the market and became a major seller, even though it could only be used with the Meridian switches. Only one other company, Octel Communications, now part of Avaya, offered a system competitive with Meridian Mail. While Meridian Mail was successful with smaller customers, Octel had market share leadership in North America, Europe and Japan. This occurred for several reasons: Octel's product line was broader in range (low capacity to very high capacity) whereas the Meridian Mail system only had small and medium capacity; Octel offered networking so larger companies could network all its voicemail systems into one company network; Octel's user interface was simpler to use and contained a much richer feature set; and Octel's systems worked with virtually every PBX in the world whereas Meridian Mail only worked with Nortel PBXs. In addition, Octel had a full voicemail product line for use in cellular networks and central office switches (for home and Centrex use), a market for which Nortel had no product.

Meridian Mail was discontinued by Nortel,[1] and has been replaced by CallPilot, which in fact uses the same features and codes as Meridian Mail, but unlike Meridian Mail, allows newer features such as Unified Messaging. Unlike older Nortel systems, where the Meridian PBXs were assigned Meridian Mail and the Norstar systems were assigned Norstar VoiceMail or Startalk Flash VoiceMail, CallPilot was branded for both the Communication Servers PBX and Business Communication Manager Hybrid/Key telephone systems.

CallPilot was one of the products acquired by Avaya in their purchase of Nortel Enterprise Solutions in 2009.